Firearm with a pivotable barrel having a spherical hump engaging a slide member



NOV. 24, 1964 w, CHARRON 3,158,064

FIREARM WITH A PIVOTABLE BARREL HAVING A SPHERICAL HUMP ENGAGING A SLIDE MEMBER Filed Jan. 23, 1962 J6 a 9a INVENTOR included a barrel received in a hollow slide.

United States PatentCfiFice Fatented Nov. 2 1%64 Eniddfid FEREARM WlTl-T A T'EVUTATELE BARREL HAVKNG A SPHERTCAL HUME" ENGAGE G A SLIDE TVEEMBER Dwayne W. Charrou, Qhieopee, Mass, asslgnor to Smith and Wesson, The, Springfield, corporation of Massachusetts Filed Jan. 23, M62, Sci. No. 168,187 5 Qlainis. (C'. 89-196) This invention relates to firearms. More particularly, this invention relates to semi-automatic pistols of improved structure for providing precise and reproducible location of certain moving parts, thereby improving the operation and increasing the accuracy of the weapon.

Heretofore, semi-automatic firearms have been provided such as the pistol disclosed in United States Letters Patent No. 2,846,925 to Joseph W. Norman. Such pistols have The barrel and slide are relcasably locked together by a lug on one engaging a groove on the other. Upon firing of the pistol, the slide and barrel recoil rearwardly together for a portion of the recoil stroke. At a predetermined point in the recoil stroke, the barrel is unlocked from the slide and the slide continues to recoil alone for the remainder of the recoil stroke to perform recocking and shell extracting functions.

This temporary locking of the barrel to the slide is provided so that the explosion gases are retained in the volume of the chamber and the barrel until the bullet has left the muzzle and t -e pressure of the gases has dropped to a safe level. Another purpose is to slow the slide and the breech bloclr or bolt which moves integrally with the slide. The acceleration of the barrel absorbs part of the explosion energy and thus the slide and bolt are accelerated to a slower speed than they would be it" the barrel did not recoil. Stress and strain on the parts are thereby reduced. Also, the danger is lessened of injury which might occur if the slide and bolt were to break the parts limiting their recoil stroke and strike the shooter.

In some such prior firearmss, the barrel has a rib engaging a groove in the slide when the barrel and slide are coaxial and at battery. Upon recoil, a carnming surface on the barrel encounters a camming surface on the frame to cause a downward pivoting of the rear end of. the barrel to disengage the rib and groove and thus unlock the barrel from the slide. The forward end of the barrel has been received in a bushing. As the rear end of the barrel pivots downwardly, the front end of the barrel pivots upwardly, thus distorting the bushing.

This distortion produces an undesirable loosencss of the barrel in the bushing so that the barrel is not located at the sa'. .e position in the slide after successive shots. This prod ices inaccuracy in shooting because the sights are mounted on the slide, but the direction of the projectile or ,bullet is determined by the barrel.

In recoil, the slide ejects the empty cartridge case and cooks the hammer. Thereafter, the recoil spring moves the slide forwardly, in a counterrecoil stroke, to pick up a fresh cartridge and chamber it into the barrel. In counterrecoil, the bolt or breech block strikes the rear end of the barrel and urges the barrel forwardly. As the barrel is urged forwardly, it engages a pin in the frame and is camnicd upwardly to lock the barrel rib in the slide groove and reorient the barrel in the slide for the next shot.

The present invention resides in the concept of providing, on the barrel, an annular spherical hump or projection engaging the inner surface of the slide or a bushing in the slide. The pivoting of the barrel, as it locks to unlocks from the slide, occurs around a pivotal axis at the spherical hump. As the barrel pivots, circular lines of contact of equal diameter, of the spherical hump, successively en age the inner surface of the slide or bushing. The bushing is not distorted because the circular lines of contact on the barrel hump, which engage the inner surface of Le bushing, are of equal diameter.

Thus, a very small allowance or clearance between the barrel hump and the inner diameter of the bushing can be employed so as to locate precisely the barrel at a position within the bore of the slide. This close fit eliminates the play or looseness which can occur where a bushing is distorted.

Further, the accuracy of the weapon is increased because the barrel is consistently and reproducibly located at the same position with respect to the slide because of the small allowance and absence of distortion of parts.

A further advantage of the invention is that the bushing or barrel can be substantially misaligned and, because the spherical hump presents lines of contact of equal diameter to the inner surface of the bushing, the parts will not jam or be distorted. In spite of such misalignment, a firearm embodying the invention can Work satisfactorily.

The invention further provides parts and structure for locating a bushin at a desired location adjustably in the slide and for readily assembling and disassembling the parts. i

For a better understanding of the invention and its other objects, advantages and details, reference is now made to the presently preferred embodiments of the invention which are shown, for purposes of illustration only, in the accompanying drawings.

In the drawings:

FIGURE 1 is a fragmentary perspective view of the barrel end of an autoloading or semi-automatic pistol according to the invention;

FIGURE 2 is a sectional View taken along the line 2-2 of FIGURE 1 and showing, in full lines, the pistol before firing; and showing, in dot-dash lines, the pistol at a point of the recoil where the barrel unlocks from the slide;

FIGURE 3 is a view similar to FIGURE 2 but showing the slide at maximum recoil position; and,

FIGURE 4 is a fragmentary sectional view of another form of the invention.

Briefly stated, the firearm according to the invention includes a conventional frame, trigger, hammer, sear, and trigger bar. A slide recoils on each shot to eject the spent cartridge case, cook the hammer, and, counterrecoils to chamber a fresh cartridge from the clip into the barrel. A bushing has a cylindrical portion threadedly received in the front end of the slide. The barrel has its front end received in the bore of the bushing when the firearm is at battery.

An annular spherical hump is formed on the barrel and engages the inner surface of the bushing along a circular line of contact. The barrel pivots on each recoil to unlock from the slide. The barrel pivots around an axis at the annular spherical hump and engages the bushing successively along lines of contact of equal diameter.

The bushing has a flange at its forward end which is notched around a portion of its periphery. A springpresscd plunger releasably and selectively engages one of the notches to releasably anchor the bushing in any desired position. The flange on the bushing forms a shoulder retaining a plate including an apertured portion received between the forward end of the slide and the bushing flange. The plate has an ear extending downwardly. A recoil spring engages the ear to press the slide, bushing, plate and barrel forwardly to battery position.

As seen in FIGURES 1 to 3, the illustrated semi-automatic or autoioading pistol includes the conventional frame Tl trigger 12, trigger guard 14, and hammer 16. The slide 13 reciprocates on frame Ti) and has mounted thereon a rear sight 26 and a front sight 22. Manual safety lever 24 is supported in slide 18- and breech block 3 that moves integrally with slide 18. The front end 28 of the slide has a bore 343 having a bushing 32 threadedly received therein.

The barrel 34 is received in slide bore 3% and has an annular spherical hump or projection 36 formed at its front end. When the pistol is at battery as shown in full lines in FIGURE 2, the hump 36 is received in the bore 33 in right circular cylindrical portion 40 of bushing 32. There is a small allowance between the diameter of hump 36 and the inner diameter of bushing portion 4% so as to provide a close fit.

The bushing 32 has a generally disc-shaped flange 42 at its front end releasably retaining a plate 44 that has an aperture formed therein and is received on cylindrical bushing portion lfi between flange 42 and'the front surface of slide 18. b

The bushing 32 can be screwed into or out of slide end 28 to various positions and is held at a desired position, as seen in FIGURE 2, by a plunger 46 having a reduced end 48 extending through a hole in plate 44 and into one of the notches 50 formed around the periphery of bushing flange 42. The plunger 46 has an enlarged end 52 slidably received in a hole 54 formed in lower slide portion 56. A compression spring 58 is received in hole 54 and yieldabl'y urges the plunger 46 to the position shown in FIGURE 2.

When it is desired to disassemble the parts, or to adjust the position of the bushing 32, the plunger 46 is pushed out of the notch St into hole 54, compressing spring 58, and the bushing 32 is then turned to adjust it or remove it from slide 18.

The slide 18, bushing 32, barrel 34 and connected parts are urged to battery by a recoil spring 69 having its rear end abutting a plate 62 engaging a shoulder 64 of frame 10. The front end of recoil spring is received in bore 65 formed in lower slide portion 56 and engages downwardly extending ear 66 of plate 44.

A guide rod in is provided for maintaining the helical shape and location of spring 60. The guide rod '76 extends through helical recoil spring 6t) and has its forward end slidably received in a hole in car 66. The rear end of rod 70 abuts plate 62 and has projecting therefrom a stud '72 engaging a cross pin 74 connected to frame 10.

The barrel 34 has a tubular portion 86, a lug or rib S2, and a groove 84 for locking with rib or lug 86 and groove 83 formed on the inner surface of the slide 18. The barrel also includes a lower rear extension 90 having a forward inclined camming surface 92 and a rear inclined camming surface 94. The forward camming surface is provided with a groove 96 for engaging cross pin 74.

For pivoting the rear end 99 of the barrel 34 downwardly, the frame 10 includes an inclined camming surface for engaging rear camming surface 94 of the barrel 34.

There now follows a description of the operation of the embodiment of the invention illustrated in FIGURES 1 to 3. In full lines in FIGURE 2, we see the pistol at battery, Where the slide 18 and barrel 34 are locked together by the engagement of ribs 32 and 86, respectively, with grooves 88 and 84. After a shot is fired, as the recoil stroke commences, the slide 18, barrel 34, bushing 32 and plate 44 all move rearwardly together or as one. When the rear camming surface 94 of barrel 34 encounters frame carnming surface 100, the rear end 99 of the barrel is pivoted downwardly, thus unlocking the ribs 82 and 86 from the grooves 8-8 and 84 as shown in dot-dash lines in FIGURE 2.

Thereafter, the slide 18, bushing 32 and plate 44 complete the recoil stroke alone to the position shown in FIG- URE 3. During recoil, the slide 18 ejects an empty cartridge case (not shown) and cocks the hammer 16. After the recoil is complete, the recoil spring 60 moves the slide 18, bushing 32 mid plate 44 forwardly until breech block 26 strikes the rear end 99 of barrel 34. The barrel is moved forwardly until forward camming surface 92 encounters cross pin 74. Thereafter, the rear end 99 of barrel 34 is pivoted upwardly by the engagement of forward camrning surface 92 with cross pin 74, as the barrel is moved forwardly with respect to the frame 10, so that ribs 82 and 86 are pressed into locking engagement with grooves 88 and 3 to lock the barrel and slide together again.

As the barrel pivots during the above-described unlocking and locking operations, Various circular lines of contact of the surface of annular spherical hump 36 successively touch the inner surface of the bushing 32. These lines of contact are all of equal diameter because of the spherical shape of the hump 36. Thereby, the parts can be constructed with a small allowance between the diameter of spherical hump 3'6 and the inner diameter of bush ing 32. The barrel is thus reproducibly and precisely located at the same position within the bushing 32 each time the pistol is brought to battery.

In the form of the invention shown in FIGURE 4, similar parts have the same reference numerals. This embodiment differs in that the spherical hump 119 is somewhat smaller than that illustrated in FIGURES 1 to 3 and there are annular grooves 112 and 114, reversely curved with respect to hump 110, on opposite sides of the hump 110, for providing a smooth joining of the hump t0 the remainder of the barrel and to avoid sharp corners.

Thus it will be seen that the invention provides a firearm wherein the barrel pivots to lock with and unlock from the slide, so constructed and designed that distortion and damage to parts is prevented; and the barrel is reproducibly returned to the same position each time the firearm is brought to battery in order to provide improved accuracy.

While presently preferred embodiments of the invention have been illustrated and described, it will be recognized that the invention can be otherwise variously embodied and practiced within the scope of the following claims.

I claim:

1. In a firearm, the combination of a slide having a bore formed therein; a bushing threadedly received in the forward end of said slide, said bushing having a cylindrical portion and a flange at the outer end of said slide, said flange having a plurality of notches formed in its periphery; a plunger removably and selectively received in one of said notches, said plunger being re ceived in said slide; a barrel received in the bore of said bushing, said barrel having a spherical hump thereon engaging the inner surface of said bushing.

2. A firearm having a frame; a slide reciprocable on said frame to recoil on each shot and counterrecoil to battery, said slide having a bore formed in its forward end; a bushing threadedly received in said forward end of said slide, said bushing having a right circular cylindrical bore formed therein, said bushing having a circular flange extending side-wardly in front of the slide, said bushing flange having a plurality of notches formed along its circular pheriphery; a plate having an aperture receiving said bushing, said plate having a portion between said slide and said bushing flange, said platehaving an ear extending from its lower portion; a recoil spring having 7 its front end engaging said ear and yieldably urging said plate, bushing and slide to battery; said slide having a hole formed therein adjacent the location of one of said notches; said plate having a hole formed therein registering with said hole in said slide; a plunger having a larger portion slidably positioned in said hole in said slide, a smaller portion receivable in said hole in smd plate and .in any of said notches, and a shoulder formed where the larger portion meets the smaller portion; a compression P unger spring positioned in said hole and urging sa d P g r to press said shoulder against said plate, said Plunger being movable to permit rotation of said bushing to a position where a different notch can be m registry with S plunger and said compression plunger spring can move said plunger to engage said different notch; 21 barrel positioned within said slide; means for locking said barrel to said slide for a portion of the recoil; means for pivoting the rear end of the barrel with respect to said slide at a point in the recoil to unlock the slide from the barrel and permit the slide to recoil without the barrel for the remainder of the recoil, said barrel having a spherical hump on its forward end positioned in said bore in said bushing when said firearm is at battery, there being a small allowance between the diameter of said hump and the inner diameter of said bushing; whereby, as said barrel pivots, said hump engages the inner surface of said bushing along successive circular lines of contact of equal diameter.

3. A firearm assembly comprising a slide member movable in a recoil stroke between a battery position and a recoil position; a barrel; means locking said barrel to said slide member for a portion of the recoil stroke; means for pivoting said barrel at a point in the recoil stroke to unlock said barrel from said slide member, said barrel having an annular spherical hump thereon, said hump engaging the inner surface of said slide member on circular lines of contact of equal diameter as said barrel pivots, the smallest inner diameter of said slide member forward of said hump when said firearm is at battery being at least as great as and not substantially greater than the diameter of said hump; whereby, when said slide member recoils, said barrel is, at a point in the recoil stroke, unlocked from said slide member and said slide member then slides rearwardly over said hump and said hump extends to a position in front of said slide member.

4. A firearm assembly comprising a slide member having a bore formed therein; a barrel positioned in said bore of said slide member; said slide member being movable in a recoil stroke between a battery position and a recoil position; means locking said barrel to said slide member for a portion of the recoil stroke; means for pivoting said barrel at a point in the recoil stroke to unlock said barrel from said slide member, said barrel having an annular spherical hump formed thereon, said hump engaging the inner surface of said slide member on circular lines of contact of equal diameter as said barrel pivots, the smallest inner diameter of said slide member and the diameter of said hump being about equal; whereby, upon recoil, said slide member and said barrel recoil as one for a portion of the recoil stroke, said barrel then pivots around said spherical hump to unlock said barrel from said slide member, and said slide member then continues to recoil for the balance of the recoil stroke and moves rearwardly relative to said hump and over said hump.

5. A firearm assembly comprising a slide member having a bore formed therein; a barrel positioned in said bore of said slide member; said slide member being movable in a recoil stroke between a battery position and a recoil position; means locking said barrel to said slide member for a portion of the recoil stroke; means for pivoting said barrel at a point in the recoil stroke to unlock said barrel from said slide member, said barrel having an annular spherical hump formed thereon, said spherical hump being fixed to said barrel during the operation of the firearm assembly, said hump engaging the inner surface of said slide member on circular lines of contact of equal diameter as said barrel pivots, the smallest inner diameter of said slide member and the diameter of said hump being about equal; whereby, upon recoil, said slide member and said barrel recoil as one for a portion of the recoil stroke, said barrel then pivots around said spherical hump to unlock said barrel from said slide member, and said slide member then continues to recoil for the balance of the recoil stroke and moves rearwardly relative to said hump and over said hump.

Reierences Cited in the file of this patent UNITED STATES PATENTS 2,153,246 Gibson Apr. 4, 1939 2,664,786 Guisasola Jan. 5, 1954 2,846,925 Norman Aug. 12, 1958 FOREIGN PATENTS 347,573 Germany Jan. 23, 1922 

1. IN A FIREARM, THE COMBINATION OF A SLIDE HAVING A BORE FORMED THEREIN; A BUSHING THREADEDLY RECEIVED IN THE FORWARD END OF SAID SLIDE, SAID BUSHING HAVING A CYLINDRICAL PORTION AND A FLANGE AT THE OUTER END OF SAID SLIDE, SAID FLANGE HAVING A PLURALITY OF NOTCHES FORMED IN ITS PERIPHERY; A PLUNGER REMOVABLY AND SELECTIVELY RECEIVED IN ONE OF SAID NOTCHES, SAID PLUNGER BEING RE- 